What kind of transformation converts the graph of f(x)=9x–4 into the graph of g(x)=–9x–4?

The transformation that converts the graph of f(x)=9x–4 into the graph of g(x)=–9x–4 is a reflection across the x-axis.

Here's why:

1. The function f(x) = 9x - 4 is a linear function with a positive slope of 9. This means the graph of f(x) is a straight line that increases as x increases.

2. The function g(x) = -9x - 4 is also a linear function, but with a negative slope of -9. This means the graph of g(x) is a straight line that decreases as x increases.

3. The only difference between f(x) and g(x) is the sign of the slope. This means the graph of g(x) is the graph of f(x) reflected across the x-axis.

In other words, every point (x, y) on the graph of f(x) corresponds to a point (x, -y) on the graph of g(x). This is the definition of a reflection across the x-axis.